Safety closure

ABSTRACT

A safety closure for a container comprises inner and outer caps with ratchet teeth formed on the skirts of the caps for abutting and turning the inner cap on the container when torque is applied to the outer cap in the application direction. When the outer cap is turned in the removal direction, the ratchet teeth will slide by each other without turning the inner cap. When a downward axial force is applied on the outer cap, radially extending teeth on the inner surface of the top end wall of the outer cap engage radially extending teeth on the upper surface of the top end wall of the inner cap so that simultaneously applied torque in the removal direction will act on the inner cap and enable removal of the closure from the container. The skirt of the outer cap is recessed at the locations of the ratchet teeth on the outer skirt to increase the skirt flexibility and enable easier back ratcheting action in the removal direction without unscrewing the inner cap from the container. The recessed areas have a pair of spaced apart vertically disposed ribs cooperating with the remainder of the outer circumferential surface of the outer cap skirt to present a generally continuous working face for automatic closure applying apparatus.

United States Patent [19] Roy SAFETY CLOSURE [75] Inventor: Gerald L. Roy, Lancaster, Pa.

[73] Assignee: Kerr Glass Manufacturing Corporation, Los Angeles, Calif.

[22] Filed: June 27, 1973 [21] Appl. No.: 374,273

Primary ExaminerGeorge T. Hall Attorney, Agent, or FirmFitch, Even, Tabin & Luedeka [5 7] ABSTRACT A safety closure for a container comprises inner and [451 Feb. 4, 1975 outer caps with ratchet teeth formed on the skirts of the caps for abutting and turning the inner cap on the container when torque is applied to the outer cap in the application direction. When the outer cap is turned in the removal direction, the ratchet teeth will slide by each other without turning the inner cap. When a downward axial force is applied on the outer cap, radially extending teeth on the inner surface of the top end wall of the outer cap engage radially extending teeth on the upper surface of the top end wall of the inner cap so that simultaneously applied torque in the removal direction will act on the inner cap and enable removal of the closure from the container. The skirt of the outer cap is recessed at the locations of the ratchet teeth on the outer skirt to increase the skirt flexibility and enable easier back ratcheting action in the removal direction without unscrewing the inner cap from the container. The recessed areas have a pair of spaced apart vertically disposed ribs cooperating with the remainder of the outer circumferential surface of the outer cap skirt to present a generally continuous working face for automatic closure applying apparatus.

6 Claims, 5 Drawing Figures SAFETY CLOSURE This invention relates to safety closures for containers which can be readily applied and removed by one having knowledge of their operation, and which are relatively safe in the hands of children because they are usually unable to manipulate the closures in the required manner to remove them from the containers.

Broadly stated, the closure described herein comprises inner and outer caps with ratchet teeth formed on the skirts of the caps for turning and applying the inner cap on the container when torque is applied to the outer cap in the application direction. When the outer cap is turned in the removal direction, however, the ratchet teeth on the respective caps slide by one another without turning the inner cap. To remove the closure from the container, it is necessary to exert sufficient downward force on the closure so that horizontally and radially extending teeth on the outer cap are brought into engagement with cooperating teeth on the inner cap and, when a torque is simultaneously applied in the removal direction, the inner cap will beturned for removal from the container. Safety closures of this general kind are disclosed in US. Pat. No. 3,055,524 to Glasbrenner and U.S. Pat. No. 3,776,407 to Cistone, both of which are assigned to the same assignee as the present invention.

Closures of these kinds should be as fool proof as possible and not open when children rotate the outer cap relative to the inner cap without the accompanying simultaneous downward thrust to engage the teeth on the ends of the inner and outer caps. To assure even under the most severe tolerances condition, that the vertically extending ratchet teeth on the skirts slide past one another without exerting sufflcient torque or friction to unscrew the inner cap when the outer cap is turned in the removal direction, the Cistone patent discloses the use of reduced thickness areas at the locations of the ratchet teeth or the outer cap to provide increased wall flexibility and a reduction in torque applied to the inner cap by the outer cap when the latter ratchets pass the inner cap. That is, the skirt of the outer cap is provided with reduced cross sectional thickness portions at the locations of the ratchet teeth to increase the outward flexibility of the skirt asthe ratchet teeth of the outer skirt slide over the cooperating ratchet teeth of the inner skirt when the outer cap is rotated in the removal direction. For instance, the back-ratchet torque may be kept under 3 torque inchlbs. with this flexing of the outer skirt wall at the outer ratchet teeth.

While the reduction in the skirt wall thickness is effective to increase the flexibility of the skirt in those areas and therefore accomplishes its intended purpose, the reduction of the thickness is achieved by providing recessed areas in the outer wall circumferential surface which has demonstrated some disadvantages, since the recessed areas necessarily result in a deviation from the desired overall circular configuration of the outer skirt surface.

Safety closures of the foregoing type have been very successful commercially and are used on a large scale by drug manufacturers and the like to comply with existing and proposed government product safety regulations, since the contents of the containers may often be quite harmful to children. Manufacturers who package products in containers which necessitate safety closures of the foregoing type often manufacture large quantities of containers and therefore utilize mass production machinery, including automatic closure applying or capping apparatus. Such automatic capping apparatus often comprise a series of driven rollers, for example, a set of four rollers disposed on opposite sides of the closures, which are driven to tighten the closures by bearing against the outer surface or working face of the outer cap skirt or, alternatively, comprise a rotating member having an opening concentrically disposed relative to the axis of rotation with the opening diameter being slightly larger than the outer cap diameter and adapted to be reduced to engage the working face with sufficient frictional contact to tighten the closure on the container during rotation. The recessed areas of the outer surface of the skirt wall necessarily define discontinuities in the working face of the skirt being acted upon by the sets of wheels in the first mentioned apparatus. Moreover, in the second type of apparatus, the compressive forces exerted on the portions extending between the recessed areas tends to cause outward flexing of the skirt wall at the recessed areas and reduce the overall bearing pressure between the skirt and the coacting surface of the apparatus. The net result is that such recessed areas have been found to disrupt the operation and thus the efficiency of such automatic capping apparatus.

Accordingly, it is an object of the present invention to provide a safety closure of the general foregoing kind which is compatible with many existing kinds of automatic closure applying apparatus in terms of the desirable efficiency, yet which continues to have the desirable increased skirt flexibility, enabling easy ratcheting of the cooperating ratchet teeth when the outer cap is rotated in the removal direction.

Other objects and advantages will become apparent upon reading the following detailed description, while referring to the attached drawings, in which:

FIG. 1 is an enlarged, perspective view of a safety closure embodying the novel features of the present invention;

FIG. 2 is a bottom view of the outer cap with portions cut away, and with the inner cap removed;

FIG. 3 is a cross-sectional view taken generally along the line 33 of FIG. 1; I

FIG. 4 is a fragmentary plan view of the top of the inner cap; and

FIG. 5 is a greatly enlarged cross-sectional view of a portion of the skirt wall of the outer cap and is taken generally along the line 55 of FIG. 1.

Turning now to the drawings, there is shown a safety closure 10 embodying the present invention and comprising an outer cap, indicated generally at 12, overlying an inner cap, indicated generally at 14, with the inner and outer caps being concentrically aligned. To fasten the closure 10 to a container (not shown), a generally cylindrical shaped skirt 16 of the inner cap 14 is formed with a container fastening means such as a spiral screw thread 18.

To apply the closure 10 by screwing the thread 18 onto the cooperatively threaded portion of a container. one or more ratchet teeth, indicated generally at 20, on the skirt 16 of the inner cap 14 project radially outwardly for engagement with one or more ratchet teeth. indicated generally at 22, on an inner side of a depending generally cylindrically shaped skirt 24 of the outer cap 12. More specifically, when the outer cap 12 is turned in the application direction (which is clockwise when viewed from the top of the closure in the drawings) toothabutment walls 26 (FIG. 4) of the ratchet teeth abut tooth abutment walls 28 of the ratchet teeth 22 to thereby interlock the ratchet teeth 20, 22, so that rotation of the outer cap in the clockwise direction will screw the inner cap onto the container. Conversely, when the outer cap 12 is rotated in the removal direction, (which is counterclockwise direction as viewed from the top of the closure) inclined or ramp surfaces 30 of the ratchet teeth 20 will contact corresponding inclined surfaces 31 of the ratchet teeth 22 located on the outer cap skirt and will slide over one another without unscrewing the inner cap. Of course, it should be understood that this back ratcheting action of the ratchet teeth will occur provided that the inner cap is sufficiently tightened onto the container. Thus, the torque required to loosen the inner cap from the container must be greater than the torque produced by the back ratcheting of the respective teeth on the inner and outer caps, or in other words, the torque exerted on the inner cap ratchet teeth by the outer cap ratchet teeth during rotation in the removal direction must be insufficient to overcome the original resistance between the thread 18 and the thread on the container. Thus, a child who merely rotates the outer cap in the removal direction will not unscrew the closure from the container.

To remove the closure 10 from the container, it is necessary to press downwardly on the outer cap 12 and simultaneously apply a torque on the outer cap skirt 24 in the removal direction. With downward pressure of sufficient magnitude applied to the outer cap 12, a plurality of radially extending teeth 32, as shown in FIGS. 2 and 3 located on the inner side of the top end wall 34 of the outer cap are moved downwardly into interlocking engagement with similarly radially extending teeth 36 on top end wall 38 of the inner cap 14. With the respective radially extending teeth 32 and 36 engaged or meshed together, a torque applied to the outer cap skirt 24 in the removal direction causes a similar torque to be translated through the engaged teeth to the inner cap which then unscrews its thread 18 from the container.

To normally maintain the respective radially extending teeth 32, 36 of the outer and inner caps 12 and 14 spaced apart from one another so that the inner cap will not be unscrewed from the container when the outer cap is rotated in the removal direction in the absence of any downwardly exerted pressure on the outer cap, the central portion 40 of the outer surface of the inner cap 14 is provided with an upwardly extending means such as a dome 42 which contacts a means such as a similar downwardly projecting resilient means or dome, herein shown to be a flexible segmented ring 44, located in the central portion on the inner surface of the end wall 34 of the outer cap.

in the prior art kind of closures, such as disclosed in Glassbrenner US. Pat. No. 3,055,534, the outer cap 12 and inner cap 14 each have a dome similar to the dome 42 shown on the inner cap 14 in FIG. 4 and also a downwardly projecting dome composed of a solid body of material that was formed on the-inner side of the outer cap end wall with its lower rounded surface abutting the upper rounded surface of the dome on the inner cap to thereby hold the radially disposed teeth 32 of the outer cap in spaced relation from the teeth 36 of the inner cap. The solid upper dome rigidified the central portion of the top end wall with the result at an annular and teeth-bearing portion of the top end wall had to be flexed by a force applied between the outer supporting skirt and the inner dome in order to bring the teeth on the two end walls into engagement with one another. In the aforementioned Cistone patent, the amount of axially directed downward force required to flex the outer cap teeth 32 into engagement with the inner cap teeth 36 was reduced by providing a dome on the central portion 45 of the top end wall 34 of the outer cap that was constructed preferably in the form of the segmented ring 44 to provide added resilience. That is, the upper dome was in the form of a segmented ring having flexible ring segments substantially similar to the segments 44 shown in FIGS. 2 and 3 which project into abutting relation with the dome 42 on the lower cap 14 and which deflect readily with depression of the center portion 45 of the upper cap 30. Preferably, the ring segments are thin in cross section and are flared outwardly from their upper to lower ends to facilitate their being deflected outwardly by the dome 42 when the center portion of the top end wall is depressed. ln this deflected condition, the ring segments are stressed and will provide a restoring force to lift the teeth 32 when the manually exerted downward forces is released.

In keeping with the present invention, the outer cap 12 of the closure 10 is preferably formed in a single piece by molding a relatively flexible resilient plastic such as polyethylene or polypropylene or the like. Thus, the top end wall 34 is made of a flexible material that is deflectible responsive to axially directed pressure. Within the interior of the outer cap 12, the series of the radially extending teeth 32 are integrally molded on the top end wall 34 and project downwardly from the inner surface 50 of the top end wall 34. The teeth 32 are elongated with the lower bottom surfaces 52 disposed in a plane spaced from and parallel to the plane of the inside surface 50 of the top end wall 34. Preferably, the teeth 32 are generally equally spaced from and angularly spaced about an axis through the center of the top end wall, with the parallel side walls of each of the teeth being generally perpendicular to the plane of the lower surfaces 52 as well as the plane of the inside surface 50. As best shown in FIG. 2, the facing side walls 56 of adjacent teeth 32 define triangularly shaped slots adapted to receive the generally triangular shaped lower teeth 36 located on the lower cap 14.

More specifically, the teeth 36 on the inner cap 14 project upwardly from an upper surface 60 which is in the same plane as the central portion 40 from which the dome 42 projects upwardly. The triangularly-shaped teeth 36 have narrow inner ends which are shown to terminate at points 62 and which diverge outwardly to an arcuate outer wall 64 which is shown in the drawings to be angularly inclined. The space between side walls 66 of adjacent teeth 36 define generally parallel sides of grooves or slots which are of sufficient size to receive theteeth 32 of the outer cap 12. Thus, both the inner and outer caps have projecting teeth and alternating slots for meshing or engaging with one another so that torque applied to the outer cap will be translated to the inner cap when the downwardly applied pressure is sufficient to engage the cooperating teeth of both caps.

For the purpose of holding the inner and outer caps 12 and 14 against separation from one another, an inwardly projecting retaining ring 70 is formed on the bottom rim of the outer cap 12 to project beneath the lower surface of the inner cap skirt 16. During assembly, the inner cap is forced inwardly into the outer cap with the retaining ring 70 being flexed outwardly by the skirt 16 until the lower surface of the skirt rim is disposed above the retaining ring 70 which is then free to snap inwardly to the position shown in FIG. 3. The inner cap I2 is preferably molded from relatively hard non-yielding plastic materials such as polystyrene,

polypropylene, bakelite or the like and the thread 18 therein is integrally molded on the inner side wall of the skirt 16. The lower portion of the skirt is also preferably provided with a thicker cross-sectional band 72 to reinforce the lower rim of the skirt. This enlarged cross-sectional band 72 projects radially outwardly into the area between the retaining ring 70 and lower ends of the ratchet teeth 20 of the outer cap 12 which, as previously mentioned, terminate at a location which is spaced away from the lower end portion of the skirt 24.

In keeping with the present invention and referring to FIGS. 2 and 5, the outer cap skirt 24 is provided with reduced cross-sectional portions or areas 80 positioned located at ratchet teeth 22 to increase the flexibility of the skirt in these portions and thereby reduce the friction and the torque applied by the outer cap ratchet teeth 22 to the inner cap ratchet 20 during a back ratcheting operation.

To provide the reduced thickness portions 80, the outer surface of the skirt wall 24 may be formed with less plastic and a reduced cross-sectional thickness area in the skirt wall forming a recessed area located inwardly on an outer circular line 82 (see FIG. 5) which defines the normally outer maximum diameter for ribs 83 defining a ribbed skirt wall 24. In the recessed areas, small ribs 85 are formed which have a lesser dimension than the ribs 83 and preferably these small ribs 85 each extend to a radially outer surface located in a plane generally defined by a line 84 which is tangent to a radial line extending through a center line 86.

In accordance with an important aspect of the present invention, each of the reduced thickness portions 80 has a pair of generally vertically disposed ribs 90 and 91 which extend from the general plane 84 of the recessed area to the circular line 82 of the skirt wall to form a continuous ribbed circumferential gripping surface for the automatic capping apparatus while still retaining the flexibility of the reduced cross-sectional area at ratchet locations to assure the outer cap ratchet teeth 22 flex radially outwardly when ratcheting past the inner cap teeth 20. Stated differently, while still retaining the wall flexibility to prevent unscrewing of the inner cap during back ratcheting, the ribs 83 and the vertical ribs 90, 91 define a working face upon which the pressure bearing surfaces of automatic camping apparatus operate to apply the closure to a container. The ribs 90 and 91 provide pressure bearing surface within the recessed areas so as to define a generally continuous working face for the automatic capping apparatus rather than the discontinuous face of the kind shown in the Cistone patent. Thus, in the event the capping apparatus is of the first type mentioned herein which includes a number of driven rollers acting on the outer cap skirt, there will be no discontinuities or gaps in the working face which would tend to cause the capping apparatus to skip or stall during the application of the closure. Alternatively, in the event the capping apparatus is of the second type which applies a generally radially inward pressure around the circumference of the closure, the vertically disposed ribs 90, 91 will abut the surrounding wall and thereby prevent outward flexing of the skirt in the recessed areas responsive to inwardly applied pressure along the circumference between the recessed areas. This permits sufficient requisite overall compressive force to be applied to the closure to enable the apparatus to apply the closure to the container during packaging operations.

As stated above, the presence of the vertically disposed ribs 90 and 9], while providing the generally continuous working face for the capping apparatus, nonetheless fail to appreciably diminish the increased outward flexibility of the skirt 24 in the reduced thickness portions during back ratcheting. Preferably, the ribs and 91 are spaced, as best shown in FIGS. 2 and 5, equidistantly from a ratchet tooth 22 and on the opposite, that is, the outer side of the outer cap skirt wall 24. Preferably, the skirt wall thickness is at its minimum adjacent the abutment wall 28 and the vertical rib 91 to assure flexing outward of its tooth 22. The increased flexibility of the reduced thickness portions 80 is, however, believed to be a function of the flexibility of the skirt wall across the entire lateral distance of the portion 80, between edges 92. Also, it is preferred that the ribs be of generally minimum lateral width and positioned generally between the outer edges 92 of the recessed area in laterally spaced relation from ratchet tooth abutment wall 28. Thus, by accurately locating the lateral position of the ribs 90 and 91 relative to the abutment walls 28 of the ratchet teeth, the increased flexibility of the skirt wall at the reduced thickness portions 80 is effectively maintained, while simultaneously providing a generally continuous working face for the automatic capping apparatus.

It should be understood from the foregoing that the present invention provides a new and improved closure which is compatible with many existing kinds of automatic closure applying apparatus and thereby enables the closure to be applied in production line packaging of containers without detrimentally affecting their operation. The closure embodying the present invention provides the above-mentioned advantage while maintaining the desirable increased flexibility of the outer skirt wall in the area of the ratchet teeth, enabling the ratchet teeth of the inner and outer cap skirts to easily ratchet by one another when the outer cap is rotated in the removal direction in the absence of downwardly applied pressure. The closure embodying the present invention is sufficiently similar to the closure described in the aforementioned patents to Cistone and Glassbrenner so that large scale retooling or new modes of manipulation for removal and replacement are not required.

While the preferred embodiment has been shown and described, it will be understood that there is no intention to limit the invention to such disclosed embodiments. On the contrary, it is intended to cover all modifications and equivalent constructions falling within the spirit and scope of the invention as defined in the appended claims.

Various features of the invention are set forth in the following claims.

What is claimed is:

l. A closure for fastening to containers, comprising: an outer cap having a circular top end wall and a cylindrically shaped skirt depending from the outer edge of said top end wall, an inner cap having a top end wall and a depending skirt-joined to the outer edge of said end wall, said outer cap overlying said inner cap and being concentric therewith, container fastening means on the skirt of the inner cap for releasably fastening on a portion of a container,radially extending teeth on the upper surface of the top end wall of the inner cap, radially extending teeth on the inner surface of the top end wall of the outer cap, vertically disposed ratchet teeth on the inner wall of said outer cap skirt, vertically disposed ratchet teeth on the outer wall of said inner cap skirt, said'vertically disposed ratchet teeth on said respective caps abutting when the outer cap is turned in an application direction to rotate the two caps together and cause said container fastening means to fasten said inner cap onto said container, said ratchet teeth of said outer cap sliding over said vertically disposed ratchet teeth on said inner cap when said outer cap is turned in the removal direction, a central portion on said inner wall of said outer cap, a central portion on said inner cap engaging said central portion of said outer cap and spacing in a vertical direction said radially extending teeth of said caps from each other, a downward force on said outer cap engaging said radially extending teeth on said inner and outer caps so that a simultaneously applied torque on the outer cap in the removal direction will act through said radially and horizontally extending teeth to turn said inner cap to release the same from the container, said skirt of said outer cap having reduced cross-sectional thickness portions adjacent said ratchet teeth on the outer cap for flexing outwardly with ratcheting of said ratchet teeth on said outer cap past the ratchet teeth on said inner cap to reduce the friction and torque therebetween to assure that said inner cap remains stationary, the outer surface of said portions having at least two spaced apart vertically disposed ribs integrally formed therein and presenting a generally continuous outer circular working face upon which closure applying apparatus can contact during application of the closure to the container.

2. A closure as defined in claim 1 wherein each of two of said vertically disposed ribs is substantially equally spaced from an outer edge of said recessed areas.

3. A closure as defined in claim 1 wherein each of said ratchet teeth on said outer'cap comprises a radially inwardly and laterally disposed inclined portion extending from the innerwall thereof to a ratchet tooth abutment wall which is generally perpendicular to said inclined portion, said ribs located on the outer surface of said skirt, and minimum cross-sectional thickness for the outer skirt wall is located circumferentially between said ribs.

4. A closure for fastening to containers and adapted to be applied to the containers using automatic application apparatus, comprising: an outer cap having a top end wall and a skirt depending from on outer edge of said top end wall, the outer surface of said skirt being generally cylindrically shaped, an inner cap having a top end wall and a depending skirt joined to the outer edge of said end wall, said outer cap overlying said inner cap in concentric relation therewith, container fastening means on the skirt of the inner cap for releasably fastening on a portion of the container, radially and horizontally extending teeth on the upper surface of the top end wall of the inner cap extending in a first substantially horizontal plane, radially and horizontally extending teeth on the inner surface of the top end wall of the outer cap extending in a second substantially horizontal plane, vertically disposed ratchet teeth on the inner wall of said outer cap skirt, vertically disposed ratchet teeth on the outer wall of said inner cap skirt, said vertically disposed ratchet teeth on said respective caps abutting when the outer cap is turned in the application direction to rotate the two caps together and cause said closure to be applied to said container, said ratchet teeth of said outer cap sliding over said vertically disposed ratchet teeth of said inner cap if the outer cap is turned in the removal direction, a central portion on said end wall of a first one of said caps facing the end wall of the other of said caps, a central portion on said end wall of the other of said caps engaging said central portion of said first one of said caps and maintaining said first and second horizontal planes in spaced relation so that said radially and horizontally extending teeth on said inner and outer caps are out of contact with one another, a sufficient downward axial force on said outer cap enabling said horizontally and radially-extending teeth of said inner and outer caps to engage one another so that simultaneously applied torque on the outer cap in the removal direction will turn said inner cap to loosen the closure from said container, said vertically disposed ratchet teeth of said outer cap being radially inwardly inclined and terminating in an abutment wall for engaging a corresponding abutment wall of the ratchet teeth of said inner cap when said outer cap is rotated in the application direction, the outer surface of said outer cap skirt wall being recessed in the area opposite said ratchet teeth to provide increased outward flexibility thereof during ratcheting responsive to rotation of said outer cap in the removal direction, said recessed area containing two generally vertically disposed ribs having their outward surface generally coextensive with the generally circular curvature of said cylindrical skirt to present a generally uniform cylindrically shaped working face for the container applying apparatus, without appreciably diminishing said increased skirt flexibility in said recessed areas.

5. A closure as defined in claim 4 wherein the outer surface of said outer cap skirt contains a plurality of vertically disposed ribs located circumferentially about said cap and in which are located within said recessed areas adjacent said two ribs.

6. A closure as defined in claim 4 wherein said two ribs in said recessed area are generally equally spaced between the outer edges of said recessed areas, the abutment wall of each of said ratchet teeth is located between said ribs, the thickness of said skirt wall being at its minimum immediately in front of each of said abutment walls. 

1. A closure for fastening to containers, comprising: an outer cap having a circular top end wall and a cylindrically shaped skirt depending from the outer edge of said top end wall, an inner cap having a top end wall and a depending skirt joined to the outer edge of said end wall, said outer cap overlying said inner cap and being concentric therewith, container fastening means on the skirt of the inner cap for releasably fastening on a portion of a container, radially extending teeth on the upper surface of the top end wall of the inner cap, radially extending teeth on the inner surface of the top end wall of the outer cap, vertically disposed ratchet teeth on the inner wall of said outer cap skirt, vertically disposed ratchet teeth on the outer wall of said inner cap skirt, said vertically disposed ratchet teeth on said respective caps abutting when the outer cap is turned in an application direction to rotate the two caps together and cause said container fastening means to fasten said inner cap onto said container, said ratchet teeth of said outer cap sliding over said vertically disposed ratchet teeth on said inner cap when said outer cap is turned in the removal direction, a central portion on said inner wall of said outer cap, a central portion on said inner cap engaging said centraL portion of said outer cap and spacing in a vertical direction said radially extending teeth of said caps from each other, a downward force on said outer cap engaging said radially extending teeth on said inner and outer caps so that a simultaneously applied torque on the outer cap in the removal direction will act through said radially and horizontally extending teeth to turn said inner cap to release the same from the container, said skirt of said outer cap having reduced cross-sectional thickness portions adjacent said ratchet teeth on the outer cap for flexing outwardly with ratcheting of said ratchet teeth on said outer cap past the ratchet teeth on said inner cap to reduce the friction and torque therebetween to assure that said inner cap remains stationary, the outer surface of said portions having at least two spaced apart vertically disposed ribs integrally formed therein and presenting a generally continuous outer circular working face upon which closure applying apparatus can contact during application of the closure to the container.
 2. A closure as defined in claim 1 wherein each of two of said vertically disposed ribs is substantially equally spaced from an outer edge of said recessed areas.
 3. A closure as defined in claim 1 wherein each of said ratchet teeth on said outer cap comprises a radially inwardly and laterally disposed inclined portion extending from the inner wall thereof to a ratchet tooth abutment wall which is generally perpendicular to said inclined portion, said ribs located on the outer surface of said skirt, and minimum cross-sectional thickness for the outer skirt wall is located circumferentially between said ribs.
 4. A closure for fastening to containers and adapted to be applied to the containers using automatic application apparatus, comprising: an outer cap having a top end wall and a skirt depending from on outer edge of said top end wall, the outer surface of said skirt being generally cylindrically shaped, an inner cap having a top end wall and a depending skirt joined to the outer edge of said end wall, said outer cap overlying said inner cap in concentric relation therewith, container fastening means on the skirt of the inner cap for releasably fastening on a portion of the container, radially and horizontally extending teeth on the upper surface of the top end wall of the inner cap extending in a first substantially horizontal plane, radially and horizontally extending teeth on the inner surface of the top end wall of the outer cap extending in a second substantially horizontal plane, vertically disposed ratchet teeth on the inner wall of said outer cap skirt, vertically disposed ratchet teeth on the outer wall of said inner cap skirt, said vertically disposed ratchet teeth on said respective caps abutting when the outer cap is turned in the application direction to rotate the two caps together and cause said closure to be applied to said container, said ratchet teeth of said outer cap sliding over said vertically disposed ratchet teeth of said inner cap if the outer cap is turned in the removal direction, a central portion on said end wall of a first one of said caps facing the end wall of the other of said caps, a central portion on said end wall of the other of said caps engaging said central portion of said first one of said caps and maintaining said first and second horizontal planes in spaced relation so that said radially and horizontally extending teeth on said inner and outer caps are out of contact with one another, a sufficient downward axial force on said outer cap enabling said horizontally and radially-extending teeth of said inner and outer caps to engage one another so that simultaneously applied torque on the outer cap in the removal direction will turn said inner cap to loosen the closure from said container, said vertically disposed ratchet teeth of said outer cap being radially inwardly inclined and terminating in an abutment wall for engaging a corresponding abutment wall of the ratchet teeth of said inner cap when said outer cap is rotated in the application direction, the outer surface of said outer cap skirt wall being recessed in the area opposite said ratchet teeth to provide increased outward flexibility thereof during ratcheting responsive to rotation of said outer cap in the removal direction, said recessed area containing two generally vertically disposed ribs having their outward surface generally coextensive with the generally circular curvature of said cylindrical skirt to present a generally uniform cylindrically shaped working face for the container applying apparatus, without appreciably diminishing said increased skirt flexibility in said recessed areas.
 5. A closure as defined in claim 4 wherein the outer surface of said outer cap skirt contains a plurality of vertically disposed ribs located circumferentially about said cap and in which are located within said recessed areas adjacent said two ribs.
 6. A closure as defined in claim 4 wherein said two ribs in said recessed area are generally equally spaced between the outer edges of said recessed areas, the abutment wall of each of said ratchet teeth is located between said ribs, the thickness of said skirt wall being at its minimum immediately in front of each of said abutment walls. 